This invention relates to a gas burner tool for use in purging a gas supply pipe.
In gas fitting, installation of new equipment or appliance generally requires the appliance be attached to a gas supply pipe carrying gas from a remote source such a main supply or a propane supply tank. In some cases the gas supply pipe is relatively long and this is particularly a problem in supply of propane where the tank is necessarily located at some distance from the main building and the appliance.
After the installation is complete, it is necessary to commence supply of gas through the pipe from the source to the installed appliance and to ignite that gas when the combustible gas reaches the appliance.
Generally the combustible gas is preceded in the supply pipe with a non-combustible gas including air, various solvents from the piping, desiccants to remove water vapor from the pipe and the like. Often these non-combustible gases include noxious smelling agents of the type added to combustible gas to provide a characteristic smell.
Up until now, gas fitters have in many cases simply turned on the gas supply so that the non-combustible gas is purged through the pipe at the installed equipment or to the outside and have waited a sufficient period of time for the non-combustible gas to escape, after which the combustible gas is ignited.
This leads to two problems. Firstly the non-combustible gas is released into the atmosphere which can release noxious materials and foul smelling gases. Secondly, if the gas fitter waits too long, the combustible gases can be released into the building where the danger of explosion either immediately at ignition of the installed appliance or subsequently when the conditions have reached the optimum for explosion to occur. This is particularly a problem with propane which is heavier than air and therefore settles at floor level so that it is less detectable. The release of the non-combustible gases can also mask the characteristic odour added to the combustible gas.
It is known to flare off purged gases to the outdoors. For example, the Canadian regulations for gas fitting CAN/CGA-B149.2-M91 define on page 14 a "purge burner" as "a burner equipped with a constant ignition source and a flame arrestor intended to burn the escaping (discharged) propane during purging operations". The same document refers to purging to the outdoors on page 63 and in 5.24.7 states that "when flaring is used to purge a piping or tubing system an approved purge burner is to be used". However no apparatus for assisting a fitter in purging a pipe primarily in an indoors situation is known to exist.
A search has revealed U.S. Pat. Nos. 4,779,608, 4,276,017 and 4,419,160, but these do not provide devices suitable for this purpose.